Rotary mixer



E. K. THOMASON 2,201,748

May 21, 1940.

ROTARY MIXER Filed Dec. 23, 1938 2 Sheets-Sheet 1 I y 1940- E. K. THOMASO-N 2,201,748

ROTARY MIXER FMMM Patented May 21, 1940 PATENT OFFICE ROTARY MIXER Ernest K. Thomason, Atlanta, Ga., assignor to Atlanta Utility Works, East Point, Ga., a corporation of Georgia Application December 23, 1938, Serial No. 247,475

7 Claims.

The present invention relates to batch mixers and particularly to such machines for mixing fertilizers, fertilizer materials, and feeds of all types, both dry and wet, provision being made for the addition of liquids to the mix. It may also be used for steaming materials.

The principal features of the invention reside in the design of the flights or blades whereby a very efiicient mixing action is obtained and gumming between the blades and the interior surface of the casing is substantially eliminated; the arrangement of the inlet and outlet openings for the mixer; the means for operating the latter; and means for introducing a liquid or gas into materials to be mixed. I

Other objects and features of novelty will be apparent from the following description taken in connection with the drawings in which Fig. 1 is an elevational view'of one end of the mixer;

Fig. 2 is an elevational view of the other end of the mixer;

Fig. 3 is a sectional elevation taken substantially on the line 3-3 of Fig. 5 and looking in the direction of the arrows;

Fig. 4 is a perspective view of the mixer, part of the casing being broken away to show the flights or blades;

Fig. 5 is a sectional elevation taken substantially on the line 5-5 of Fig. 3 and looking in the direction of the arrows.

Referring to the drawings, the main parts of the mixer comprise a hollow cylindrical casing A having inlet and outlet openings B and C located in one lateral side of the casing. Gates are provided to control these openings and a housing D is spaced from and surrounds these openings and gates.

More specifically the casing comprises the hollow cylindrical shell ||l having end closures H and I2. This casing is stationary and is mounted on a shaft I3 carried in bearings l4 and I5 mounted respectively on the supports l6 and I1. Suitable stuffing boxes, as shown at l8, are provided where the shaft |3 passes through the two end heads H and I2 thereby preventing the passage of dust and gas fumes from the interior of the casing.

housing by means of flanges 23 and 24 integral with the cast section. This casting at each end has sufficient bearing for the shaft to turn in. The inlet and discharge openings B and C extend substantially the full width of the discharge housing, running lengthwise with the shell.

The intake and discharge gates are mounted on the shaft 2|. Two bracket castings 23 are keyed to the shaft 2| and actuate the intake gate from its closed position shown in section in Fig. 3 to the open position shown in dotted lines in the same figure. The shaft 2| is operated by a hand wheel 24. For this purpose an arm 25 fixed to rotate with the wheel through a link 26 operates the lever 21 fixed to the shaft 2|. The arm 25 and link 25 constitute in effect a toggle mechanism. When this hand wheel, as viewed in Fig. 1, is turned in a clockwise direction, the toggle mechanism turns shaft 2| in the same clockwise direction and thus opens the intake gate. A reversed rotation closes the gate.

The shaft 28 on which the hand wheel 24 is loosely mounted is fixed to the discharge housing in any suitable manner. At the end of the shaft opposite the wheel 24 is another hand wheel 29 for operating the discharge gate. The discharge gate C is carried by two bracket castings 30 loosely mounted on a shaft 2|. The discharge gate is opened or closed by means of toggle link 3| and connecting link 32 attached to the gate at one end by the lugs 33. There are two of these toggle mechanisms, the links 3| of which are fixed on shaft 34 which turns freely in bearings at each side of the housing. This shaft 34 is operated by means of hand wheel 29 loosely mounted on shaft 28 through the means of arm 35, link 36 and arm 31. When the shaft 34 is turned in a clockwise direction, as viewed in Fig. 3, it moves the link 32 to the position shown in dotted lines in Fig. 3 thus opening the discharge door to the dotted line position. Link 32 has an extension with a pin 38. When shaft 34 is turned in a clockwise. direction, as viewed in Fig. 3, rotation of the link 32 is stopped when the pin contacts the curved section of the toggle link 3|. The curved section of this toggle link is such that the extended pin and link 32 contact this toggle link beyond the straight line drawn through the axes of link 32 the connection of toggle arm 3| to the link 32, the pin 38, and shaft 34. This forms what may be termed a past center closing, locks the mechanism, and the discharge gate cannot be opened unless the shaft 34 is again revolved in a clockwise direction.

The housing D is provided with supply opening 39 at the top thereof and a discharge opening 40 at the bottom. The supply opening 39 is controlled by a plate 4| secured to the rotatably mounted shaft 42. When it is desired to convey materials into the mixer shell, the intake gate B is opened, as already explained, and the hopper or supply valve gate 4! is swung downwardly to the dotted line position shown in Fig. 3. It will be noted, from the dotted line positions of gate B and supply valve 4!, that they cooperate to act as guides to direct the material furnished through the supply opening into the interior of the casing of the mixer. The hopper or supply gate 4! is operated by hand lever 43 mounted on pivot 44 and which may be latched into closed position of the valve by means of a lug angle 45 attached to the side of the discharge housing. At the free end of the lever 43 is pivoted a rod 46 that extends through a bore in block 41 and at its free end has an abutment 48. Between the abutment 48 and the block 47 is a compression spring 49. On shaft 42 is an arm 50 that engages block 47. To open the supply gate or valve 4| the lever 43 (Fig. 2) is swung in a clockwise direction and this turns arm 50 swinging the gate 4i downwardly. To close the valve, the lever is moved in the opposite direction and spring 49 constitutes a further means of holding the gate closed tight.

The flights or blades for effecting the mixing extend the full length of the mixer shell and revolve as close to the interior surface thereof as possible. As shown, there are four flights, two of the flights being what might be termed righthand spiral and two left-hand spiral. For carrying the flights, there are provided two cast spiders and 52 rigid with the shaft l3 and located near the heads of the casing. Four heavy arms 53 are bolted to the spiders and the mixer flights 54 and 55 are made fast to the ends of said arms. It will be noted that adjacent arms 53, as viewed in Figs. 3 and 4, are disposed at about 45 to each other. The two spiders 5! and 52 are disposed on the shaft Is at 90 with respect to each other. This particular method of mounting the blades makes the flights right hand and left hand when the flights are connected from one spider to the other.

As the discharge gate is located at the center of the casing, it is desirable to have the flights inclined with respect to each other in the direction of rotation so that the materials can be discharged cleanly from the mixer. The right and left hand flight action moves the materials lengthwise back and forth of the shell, as well as revolving through the materials, lifting them up, dropping them, and thoroughly agitating and mixing them. It will be noted further, referring to Fig. 3, that the front faces of the flights or blades are not radially disposed with respect to the axis of rotation, but are inclined away from the direction of rotation, preferably at an angle of about 45. This gives a hook to the flights causing a shearing action between the materials and the interior of the casing rather than a scrubbing action, which would be obtained if the flights were on a straight radial line with respect to the center of the casing. This arrangement also eliminates gumming of the materials on the interior of the casing. Since the flights 54 and 55 are inclined at an angle to the radius extending from the shaft l3 around which theywhen rotating in a clockwise direction and the gate controlling the discharge or outlet opening is in open position dash the mixed materials outwardly through said opening.

At the top of the casing, extending for about three-fourths of the length thereof is a dome 56, open into the interior of the casing. In this dome are one or more pipes 57 drilled with a sufficient number of holes to permit fluids to be sprayed into the mixer. Suitable connections to these pipes can be made for the supply of ammonia, liquids, steam, etc.

As shown in Fig. l, the shaft l3 carries a gear 53 meshing with a pinion 59 that is rotated by pulley 60. This constitutes the driving mechanism for the flights.

Although the machine is designed principally for mixing fertilizers and fertilizer materials, it may be used for feeds of all types, both dry and wet, fluids being added through the pipes in the dome 56. It may be used for steaming materials as steam may be injected through the pipes.

If desired, materials from the supply opening or gate 4| may entirely by-pass the mixer and drop straight through the discharge housing. This feature is very desirable in the fertilizer in dustry and is quite frequently resorted to.

From the foregoing description, it is thought that the operation of the mixer will be fully understood and no further description on this point is necessary.

Although a specific form of the invention has been described in detail, it is to be distinctly understood that the invention is not limited to this one form, but includes modifications and changes coming within the scope of the appendant claims.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. A rotary mixer, including in combination, a stationary cylindrical casing having contiguous inlet and outlet openings in one lateral side, a housing spaced from and surrounding said openings, gates in said housing controlling said openings, means to operate said gates, a controlled supply opening at the top of the housing, a discharge opening at the bottom of the housing, and rotatable flights within said casing and coacting with the internal circumferential surface of said casing to thereby exert a shearing action between the materials being mixed in said casing and said internal surface to eliminate gumming of such surface by said materials when said flights are rotating in a counter-clockwise manner, and assist in ejecting the mixed materials from said casing through said outlet opening when said flights are rotating in a clockwise manner and the gate controlling such opening is in open position.

2. A mixer according to claim 1 wherein the inlet gate is pivoted at its lower portion and swingable to an open position where it acts as a guide to deflect material entering through the housing supply opening into the casing.

3. A mixer according to claim 1 wherein the inlet gate is mounted to swing to an open position about an axis parallel to its lower edge, a plate closing the housing supply opening and pivoted to swing downwardly to open the same, said gate and plate being disposed to cooperate in open positions to act as guides to deflect material entering through the housing supply opening into the casing.

4. A mixer according to claim 1 having a shaft rotatably mounted in said housing horizontally between said gates, means securing the inlet gate to rotate with the said shaft, means to rotate said shaft, means loosely mounting the discharge gate on said shaft, and means to operate the discharge gate.

5. A mixer according to claim 1 wherein the means for controlling the supply opening comprises a plate mounted on a rotatable shaft, an arm on the shaft, an operating lever pivoted on the housing, a block on the end of the arm having a central bore, a rod pivoted to the free end 'of the lever and extending through said bore having an abutment at its free end, and a compression spring on said rod disposed between said block and abutment.

6. A mixer of the type described, including in combination, a hollow stationary cylindrical casing having an inlet opening disposed above and contiguous to a discharge opening at one lateral side, gates controlling said openings, and rotatably mounted flights in the casing extending longitudinally substantially the length of the casing and cooperating with its interior cylindrical surface, adjacent flights being inclined in opposite directions with respect to their direction of rotation, to thereby exert a shearing action between the materials being mixed in the casing and said interior surface to eliminate gumming of such surface by said materials when said flights are rotating in a counter-clockwise manner, and assist in ejecting the mixed materials from said casing through said discharge opening when said flights are rotating in a clockwise manner and such opening is in open position.

7. A mixer of the class described, including in combination, a hollow stationary cylindrical casing having an inlet opening contiguous to a discharge opening at one lateral side of its cylindrical surface thereof, gates controlling said openlugs, and rotatably mounted flights in said casing extending longitudinally substantially the length of the casing and cooperating with its interior cylindrical surface, said flights com-prising pairs of adjacent flights which are inclined in opposite directions with respect to their direction of rotation, the front face of each flight being inclined to a radial plane through the axis 

